Sanders snags 1st congressional endorsement

Rep. Raul Grijalva (D-AZ) joins veterans, servicemembers and aspiring recruits to call on Congress and President Barack Obama to move forward with immigration reform at the U.S. Capitol November 12, 2014 in Washington, DC. The news conference participants called on Obama to 'go bold and go big' and to use his executive authority to reform immigratoin if Congress could not get the job done.(Photo: Chip Somodevilla/Getty Images)

Arizona's Democratic Rep. Raul Grijalva will announce his official endorsement of Bernie Sanders for president on Friday at a rally in Tucson, according to Grijalva's press secretary.

This is Sanders’ first endorsement from a member of Congress.

Grijalva's endorsement was first reported by the Los Angeles Times.

Sanders has trailed far behind former Secretary of State Hillary Clinton in garnering support from the Democratic Party for his presidential bid. Clinton has secured 354 endorsements from representatives, senators and governors, according to FiveThirtyEight.

Even Sanders' fellow Democratic senator, Patrick Leahy, has announced his support for Clinton.

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Bernie Sanders and Davenport Mayor Bill Gluba walk to the elevator after a coffee sit-down at City Hall in Davenport, Iowa, on May 29, 2015.(Photo: EMILIE STIGLIANI/FREE PRESS FILE)

This endorsement comes at a critical time for Sanders as he prepares for the first Democratic debate on Tuesday. Sanders will also make a video appearance on Monday at New Hampshire's No Labels convention.

Despite a lack of support from the party establishment, Sanders has risen in the polls since his May campaign kickoff. In the latest national survey by Public Policy Polling, Sanders received 24 percent support among likely Democratic voters. Clinton received 42 percent.